1 files changed, 68 insertions, 8 deletions

diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index c15fb8c24ad2..1a79df9f739f 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -16,7 +16,7 @@ enum chain_mode {
 
 struct callchain_node {
         struct callchain_node   *parent;
-        struct list_head        brothers;
+        struct list_head        siblings;
         struct list_head        children;
         struct list_head        val;
         struct rb_node          rb_node; /* to sort nodes in an rbtree */
@@ -49,9 +49,30 @@ struct callchain_list {
         struct list_head        list;
 };
 
+/*
+ * A callchain cursor is a single linked list that
+ * let one feed a callchain progressively.
+ * It keeps persitent allocated entries to minimize
+ * allocations.
+ */
+struct callchain_cursor_node {
+        u64                             ip;
+        struct map                      *map;
+        struct symbol                   *sym;
+        struct callchain_cursor_node    *next;
+};
+
+struct callchain_cursor {
+        u64                             nr;
+        struct callchain_cursor_node    *first;
+        struct callchain_cursor_node    **last;
+        u64                             pos;
+        struct callchain_cursor_node    *curr;
+};
+
 static inline void callchain_init(struct callchain_root *root)
 {
-        INIT_LIST_HEAD(&root->node.brothers);
+        INIT_LIST_HEAD(&root->node.siblings);
         INIT_LIST_HEAD(&root->node.children);
         INIT_LIST_HEAD(&root->node.val);
 
@@ -61,15 +82,54 @@ static inline void callchain_init(struct callchain_root *root)
         root->max_depth = 0;
 }
 
-static inline u64 cumul_hits(struct callchain_node *node)
+static inline u64 callchain_cumul_hits(struct callchain_node *node)
 {
         return node->hit + node->children_hit;
 }
 
-int register_callchain_param(struct callchain_param *param);
-int callchain_append(struct callchain_root *root, struct ip_callchain *chain,
-                     struct map_symbol *syms, u64 period);
-int callchain_merge(struct callchain_root *dst, struct callchain_root *src);
+int callchain_register_param(struct callchain_param *param);
+int callchain_append(struct callchain_root *root,
+                     struct callchain_cursor *cursor,
+                     u64 period);
+
+int callchain_merge(struct callchain_cursor *cursor,
+                    struct callchain_root *dst, struct callchain_root *src);
+
+bool ip_callchain__valid(struct ip_callchain *chain,
+                         const union perf_event *event);
+/*
+ * Initialize a cursor before adding entries inside, but keep
+ * the previously allocated entries as a cache.
+ */
+static inline void callchain_cursor_reset(struct callchain_cursor *cursor)
+{
+        cursor->nr = 0;
+        cursor->last = &cursor->first;
+}
+
+int callchain_cursor_append(struct callchain_cursor *cursor, u64 ip,
+                            struct map *map, struct symbol *sym);
 
-bool ip_callchain__valid(struct ip_callchain *chain, const event_t *event);
+/* Close a cursor writing session. Initialize for the reader */
+static inline void callchain_cursor_commit(struct callchain_cursor *cursor)
+{
+        cursor->curr = cursor->first;
+        cursor->pos = 0;
+}
+
+/* Cursor reading iteration helpers */
+static inline struct callchain_cursor_node *
+callchain_cursor_current(struct callchain_cursor *cursor)
+{
+        if (cursor->pos == cursor->nr)
+                return NULL;
+
+        return cursor->curr;
+}
+
+static inline void callchain_cursor_advance(struct callchain_cursor *cursor)
+{
+        cursor->curr = cursor->curr->next;
+        cursor->pos++;
+}
 #endif  /* __PERF_CALLCHAIN_H */